fangcheng.txt

接二元一次方程组 初级java学习gui元件最基本的使用！

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class TestWindow extends JFrame{
	private JLabel aLabel,bLabel,cLabel;
	private JTextField aField,bField,cField,displayField;
	private JButton computeButton,exitButton;
	public TestWindow(){
		super("计算ax^2+bx+cx=0的根");
		Container container=getContentPane();
		container.setLayout(new FlowLayout());
		
		aLabel=new JLabel("a");
		aField=new JTextField(10);
		container.add(aLabel);
		container.add(aField);
		bLabel=new JLabel("b");
		bField=new JTextField(10);
		container.add(bLabel);
		container.add(bField);
		cLabel=new JLabel("c");
		cField=new JTextField(10);
		container.add(cLabel);
		container.add(cField);
		
		displayField=new JTextField(30);
		displayField.setEditable(false);
		container.add(displayField);
		
		computeButton=new JButton("计算结果");
		container.add(computeButton);
		
		exitButton=new JButton("推出");
		container.add(exitButton);
		
		ActionEventHandler handler=new ActionEventHandler();
		computeButton.addActionListener(handler);
		exitButton.addActionListener(handler);
		setSize(600,140);
		setVisible(true);
		
		
        }
        
        
        public static void main(String args[]){
        	TestWindow window=new TestWindow();
        	
        }
        private class ActionEventHandler implements ActionListener{
        	public void actionPerformed(ActionEvent event){
        		if(event.getSource()==exitButton)
        		System.exit(0);
        		else if(event.getSource()==computeButton){
        			String a=aField.getText();
        			String b=bField.getText();
        			String c=cField.getText();
        			float  ai=Integer.parseInt(a);
        			float  bi=Integer.parseInt(b);
        			float  ci=Integer.parseInt(c);
        			if(bi*bi-4*ai*ci>=00){
        				float d1=(float)(-Math.sqrt(bi*bi-4*ai*ci)-bi)/(2*ai);
        				float d2=(float)(Math.sqrt(bi*bi-4*ai*ci)-bi)/(2*ai);
        				String e=String.valueOf(d1);
        				String f=String.valueOf(d2);
        				displayField.setText("结果:x1="+e+"  x2="+f);
        				
        			}
        			else displayField.setText("此方程无解");
        		}
        	}
        }







}